1. Field of the Invention
This invention relates to industrial heat treating furnaces and more particularly relates to molten salt bath furnaces of the type in which the heat is electrically generated, the molten bath constituting the resistor. Specifically, the invention relates to the use of air cooled electrodes in heat treating furnaces in place of water cooled electrodes which have been used extensively heretofore.
2. Description of the Prior Art
The prior art shows electrically heated molten salt bath furnaces which utilize water cooled electrodes. One prior art patent utilizing water cooled electrodes is the Upton U.S. Pat. No. 2,355,761 dated Aug. 15, 1944 entitled "Electrically Heated Molten Bath Furnace". The water cooled electrodes employed therein take a considerable amount of water to cool the electrodes and the cooling water, after use, is either drained to the sewer or recirculated through an expensive water recirculating system. Another problem with a water cooled electrode is that the cooling hole provided therein frequently becomes clogged or plugged due to the presence of lime or iron in the water. The minerals settle in the hole blocking the coolant passage and thereby preventing the water from circulating through the electrode. Also a water cooled electrode system employs an elaborate and expensive plumbing system which frequently fails due to ruptured pipes or hoses. Such breakage can create a safety hazard in the event the water contacts the molten salt.